Questions tagged [vector]

A coordinate-based data model that represents geographic features as points, lines, and polygons.

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1answer
47 views

Calculating areas of polygons that match with overlapping raster threshold value?

I have a polygon of districts (districts.shp) and a raster of rainfall (rainfall.tiff). I want to calculate the area of each district that saw rainfall greater than various numbers. I'd like to ...
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24 views

Can only select certain polygons

I have only one vector layer on my map, and it's not letting me select some polygons. For instance, this is what happens when I try to select a certain polygon (the yellow outline with the blue star ...
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1answer
54 views

Map based on highest percentage from different variables

I've the 8 social classes (see under) for +- 900 polygons. I would like to create a new column that keep only name of the main social class for each row (based on the percentage). After that I would ...
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2answers
72 views

Seeking tool to work out overlap between two polygon layers and their statistics using QGIS

I have two polygons in QGIS. One is a land-use map, which polygons that include different types (forest, agriculture, urban etc). I also have a vector polygon that represents a flood extent. I want to ...
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0answers
73 views

Fixed distance buffer is oval in QGIS?

I want to create circles of diameter 20m in QGIS. I create a point and then use vector - geoprocessing tools - fixed distance buffer. My problem is that the size is crazy and worse, the shape is not a ...
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51 views

Computing Moran's I for vector data in GRASS

Does GRASS allow for computing Auto-Correlation using Moran's I statistic from vector files. GeoDa and ArcGis can do this. But seems grass lacks this functionality https://grass.osgeo.org/grass76/...
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1answer
66 views

Fixing self-connect polygon in QGIS 3.2

I'm trying to clip a soil map layer and am getting invalid geometry that affects my clip result. The problem appears to be a self-intersecting polygon. I've tried using the 'check geometries', and ...
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2answers
86 views

How to convert multiple shapefiles of different geometries into a georeferenced raster

I have multiple shapefiles extracted from OSM vector data, as shown in the image bellow: How can I render this into a raster of a specified resolution? Is there a way to do that using QGIS or ...
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3answers
118 views

Converting raster pixels to vector cells?

Is there any way to convert raster pixels to vector cells? I mean each pixel to a polygon. I tried the SAGA tool 'Raster values to points' by choosing cells option instead of nodes option. As a ...
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0answers
32 views

Clipping features with the attributes of another feature

I have a vector polygon for a catchment which contains numerous subbasins. In addition, I also, possess another vector polygon showing the impervious areas of the catchment. What I want to do is ...
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1answer
80 views

Buffer with unknown distance by adding numerical values of a column until a maximum

In my QGIS project, I have a vector of polygons representing slope zones around an archaeological site and I want to calculate the area which is necessary to supply the ancient population with a ...
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1answer
69 views

Summing amount of vector points in area of another vector using Google Earth Engine?

So I have 2 layers each are both vectors and not images. here the link: https://code.earthengine.google.com/e7aec6c9683ed40a959a01a7ed5dd31f I have written some basic code to display the data which ...
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76 views

Creating memory layer with .png image using PyQGIS?

In Aligning Raster and vector layer using PyQGIS when they do not match?, someone gave a solution for creating a point memory layer to correctly align a raster image with a vector. I am wondering ...
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3answers
169 views

How can I save a vector layer to memory (or is there a reason QGIS doesn't allow this)?

It's impressive how many different vector file formats QGIS (using ver 3.6.0) allows me to save a layer as: But as far as I can tell, QGIS doesn't allow me to save a vector layer to memory. In my ...
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0answers
129 views

PyQGIS raster image shifted from vector shapefile

I previously asked a question about my raster image being larger and shifted over from my vector image here, but now I realize that the raster image is only shifted to the left and up from the vector ...
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0answers
45 views

Storing a large amount of vector layers on PostGIS

I'm developing a web application where PostGIS will be used as a vector tile server backend to serve mvt tiles. For each user of the application at least one vector layer will be created. So, ...
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1answer
122 views

PyQGIS code for Merge Vector Layers

I've been trying to automate the merge vector layers via PyQGIS but I can't seem to get it right. This is my code: import os import processing loc = r"C:\Users\loc" os.chdir(loc) shapelist = os....
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0answers
88 views

Can relation reference in QGIS and QField be used to fill stochastic matrices?

I am a novice GIS user and am just seeing the potential for relations in my work. A problem I've come across and would like a solution to it. I have two stochastic matrices (risk matrices) that ...
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0answers
52 views

Referencing an output in an expression in process modeler

In the process modeler, I'd like to reference an output of a previous step as one of the parameters of an algorithm. In this case, the previous step was clipping a large raster and I want to use the ...
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2answers
89 views

Selecting latest date with QGIS field calculator?

My shapefile contains columns like "Street", "number" and "date". What I want to do is, to find the latest date (where we have done house services). If we have 2 dates for one house number ("number")...
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2answers
108 views

QGIS how to sum a certain vector field inside a polygon and populate a field in the polygon?

I have a polygon with vector point civic addresses inside it. Each civic address has a different number residence. I want to sum the total number of residence inside that polygon and it populate a ...
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0answers
41 views

QGIS 3.4 (mac) std::bad_alloc error

I get the above error when trying to add a new raster or vector layer. Does anyone know how to correct it as the resulting projection is nowhere near where I need it.
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2answers
83 views

QGIS Hex grid with the shape of vector

I'm trying to make a hex grid net with the shape of polygon. Unfortunately, the grid net is in the rectangle shape (see the screenshot). Any advice how to do it?
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2answers
49 views

Unite several polygons that share boundaries in QGIS

My study zone is in the middle of two geologic maps with two different shp files. Is it possible to remove the boundaries of the polygons between these two maps that are created at the union of ...
2
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1answer
52 views

average weighted value by region with use of Voronoi in Qgis

I have a vector layer of Voronoi polygons. This layer has three columns -longitude, latitude, Z-value. I need to cut polygons by mask of administrative area and then I need to calculate average-...
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0answers
13 views

Get visible polygon form one point (visibility graph with one point)

Problem I would like to get the visibility of one point in regard to a polygon layer. E.g. which island can I see from the beach. What I found It's possible to get a visibility graph via Grass v....
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0answers
439 views

Error in reproject vector file using GeoPandas

I have a vector file (in this case shp file) and I read it with GeoPandas (gpd). vector_folder = r'C:\poly' vector_file = 'poly.shp' df = gpd.read_file(os.path.join(vector_folder,vector_file)) df ...
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2answers
99 views

Calculate the percentage of a Line passing through Polygons

I have a polygon layer of a region (100% coverage, no overlaps) and a line layer in the same region. I want to calculate for each line to which percentage it crosses certain polygons. I have seen ...
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1answer
83 views

Creating new lines based on another line feature and point feature using QGIS?

I have line layer (roads) and point layer (milestones) and I need to create a new line layer based on roads layer, where the start and the end points will be milestone points. Can you advise me some ...
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1answer
207 views

QGIS 3.6: Vector “Polygons to Lines” missing

I use the tool Vector-->Geometry Tools-->Polygons to Lines all the time. It is in the menu up until 3.4. In 3.6, that menu item is no longer available. Where did it go? Is there another way to do ...
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3answers
72 views

Calculating the shortest distance coordinate to vector layer

I want to calculate the nearest distance from each coordinate in a vector layer containing more than 17 000 coordinates to another vector layer. I tried the GRASS v.distance tool but it gives the ...
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3answers
1k views

QGIS split vector layer gives me GPKG files but I need shp files

QGIS 3.6.0 I am new to QGIS software and not very technical on its deep workings. I am trying to split a .shp file using split vector layer. I need .shp file outputs but it auto creates .gpkg files. ...
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0answers
206 views

Does any version of QGIS support GDB 10.5?

Does any version of QGIS support GDB 10.5? I have a GDB 10.5 file that I need to open in QGIS and I can't. I'm using QGIS 3.6. The file is named Virginia_Parcel_Dataset_2018Q4.gdb -- it can be ...
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115 views

ArcGIS: Train Support Vector Machine Classifier on a Segmented Raster

I have a raster (.jpg) which I have segmented utilising Segment Mean Shift to smooth out JPEG artefact (aim is to classify it as accurately as possible for conversion into vectors). START .JPG Input ...
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1answer
24 views

Keeping minimum when converting from shapefile to raster?

I have a shapefile that I am trying to convert to raster. The shapefile has overlapping polygons. I would like to keep the minumum value of these overlapping polygons when converting to raster. ...
2
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1answer
152 views

How to make a rectangle of an exact size/aspect ratio in QGIS?

Is there any way in QGIS to make a vector layer with a rectangle of an exact size or aspect ratio? Ideally, it would be nice if the rectangle from extent tool could be limited to a set aspect ratio, ...
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0answers
170 views

Vector Rasterize Error

I am running QGIS 3.4.4 With GRASS 7.4.4 and I get an error while rasterizing a vector layer and I don't know why. The same error pops up while using GDAL->Rasterize(vector to raster) and while using ...
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1answer
74 views

Translating vector by raster DEM data in QGIS?

I'm trying to follow the set of instructions here: https://twitter.com/imhere_asia/status/1023055838787690496 [EDIT] Pasting the instructions here for reference so people can avoid twitter. ...
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24 views

Prevent Export/Save As of Vector Layers/Shapefiles

I have created a database using postgreSQL and created multiple users assigned with different roles Some of the users can only select and view the data and not update or delete any record. It works ...
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1answer
186 views

Exporting crown boundaries from tree segmentation in R?

I am using lidR package to segment my trees using lastrees directly from the points clouds. The function works fine, however I would like to export to vector file the canopy boundaries from ...
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1answer
83 views

How to batch geocode country names to polygons? [closed]

I have .xlsx dataset file with column "Country Name" and "Country Code" which have text records. I would like to geocode (assign) it to adequate country polygon in batch mode. The expected result ...
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1answer
54 views

QGIS3 How to export shapefile symbology to scale?

I'm looking how to export in QGIS3 a vector layer with a determined scale. It was straightforward in QGIS2 when I was exporting to a shapefile I had the option symbology scale but it disapear in QGIS3 ...
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2answers
312 views

Create line segments at point coordinates in QGIS

I have a point vector layer with angle field. How can I create line segments at these points with certain length and angle? I did this with style options but I need this physically as lines vector ...
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0answers
28 views

Vector to grid - Computing statistics by grid cells

I have a vector point data from drifting buoys (speed, direction, sst, slp) that I want to analyse in a grid. What are the right tools for this? Example of my points data below. Each point has the ...
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0answers
60 views

QGIS Display Attributes as Z Value for Point Shapefile?

I would like to create a state map that displays a 3D bar chart for each of 20 colleges (mapped as points) showing the percent share of engineering degrees earned by award level (i.e., assoc, ...
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1answer
17 views

How to prevent labels from a vector file to overlap the raster file?

I have vector file of say Sewer lines with diameter as their labels. Against some of the sewer, georef. images are placed. While displaying all together, line labels do appear over the raster file. I ...
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1answer
245 views

How to properly import corine landcover 2012 (vector file) in QGIS?

I'm fairly new to QGIS (using version 2.18.25), so I may be missing something quite basic. I'm using the Corine landcover (clc12_Version_18_5.gdb) in my project. It's a very large dataset (3GB) so it ...
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1answer
319 views

Reclassifying shapefile using ArcGIS Desktop?

So I have a shapefile consisting of 1000 polygon records. I would want to reclassify one field "Value" into a new blank field named "New Value". As an example: record = 1; value = 25.6 record = 2; ...
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0answers
20 views

ERROR in R - it cannot support the vector

I did use the function crop and mean for 434 rasters in Rstudio. Each one is very big, it corresponds almost like 1/4 of Brazil. Now I want to calculate the standard deviation between these 434 ...
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1answer
62 views

Exporting vector from raster classification gives deformed vector in Google Earth Engine?

I am very new with Google Earth Engine and I try to make a landcover classification using Sentinel-2 imagery to get the urban area over a very large area (country wide ideally). I was able to ...